CYSTIC TUMOURS. 443 



or a damp atmosphere upon elevated situations, will act as causes 

 of broncho cele. 



It is detected by a soft fluctuating swelling of the thyroid 

 body, occupying one or both sides of the larynx. Treatment : 

 Eemoval of apparent causes, with good food, warm shelter, and 

 the administration of iodine or its salts. If these are not suc- 

 cessful, and if the swelling interfere with the usefulness or value 

 of the patients, paracentesis must be performed, and the sacs 

 afterwards injected with tincture of iodine. 



Of the compound or proliferous cysts we have examples in 

 cysts bearing cysts, constituting the compound serous cysts of 

 the ovaries, thyroid body, and mammary gland ; in cutaneous 

 proliferous cysts, or cysts bearing hair and skin ; and in denti- 

 gerous or teeth-bearing cysts. 



Of the cutaneous cysts we have many examples from the 

 horse, cow, and dog. Hair-bearing cysts have been found in 

 parts far removed from the outer surface of the body, as in the 

 brain and ovaries. 



Mr. Paget says, that " it is perhaps only during the vigour of 

 the formative forces in the foetal or earliest extra-uterine periods 

 of life that cysts thus highly organized and productive are ever 

 formed. The sebaceous, epidermal, or ciiticidar cysts that grow in 

 later life are imperfect, impotent imitations of these, yet clearly 

 are the same disease, and are therefore most naturally classed 

 wdth the proliferous cysts, needing only to be named according 

 to their contents." 



The truth of the above quotation must be apparent to all who 

 have seen cases of this kind, for they are generally found in 

 very young animals as small hard tumours, some of them having 

 a very small aperture through which some of their contents can 

 be pressed out, whilst the majority of them are without any 

 aperture whatever. When cut into, they are found to contain hair, 

 along with sebaceous matter, forming a globular and hardened 

 mass, enclosed in a cyst with a laminated pliable wall, lined with 

 epidermis and covered with hair. 



The most important compound cystic diseases that come under 

 the notice of the veterinarian are — 1st. That where multiple 

 cysts, or 2d., dentigerous cystic growths, invade the superior 

 maxillary sinuses. (Photo-lithograph, Plate II., Pig. 8, is an 

 illustration of the former, and Pig. 9 of the latter.) 



